PPRuNe Forums - View Single Post - Cold temp corrections on LNAV appr
View Single Post
Old 12th Nov 2017, 18:29
  #9 (permalink)  
EMIT
 
Join Date: Aug 2007
Location: The Netherlands
Age: 67
Posts: 288
Likes: 0
Received 0 Likes on 0 Posts
Platform

Quote:
Personally, I wouldn't feel comfortable flying an uncorrected platform altitude in order to intercept the vertical profile later (especially in IMC) because terrain clearance could be substantially reduced. But I don't know what the law is regarding this.
Unquote

According to the law, you need TO CONSIDER the effects of temperature on the approach.

Take a situation where the MSA in the area of the approach is 1.700 ft and the platform altitude is 2.000 ft.
I would consider the effect of temperature such that, as long as the required correction is less than 300 ft, the (indicated) platform altitude of 2.000 ft is still above the (truely required) Minimum safe Sector Altitude of 1.700 ft.
In that case, keeping it simple and starting from 2.000 ft would be safe.

For adjustment of descent point DME, the simple one in three rule is applicable - a 3 degree descent is approximately 300 ft per nautical mile, so if your correction would be 200 ft, that would equate to two thirds of a nautial mile, in other words, start descent 0.7 nm later than published distance.

Hope this helps.
EMIT is offline